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F. THOMAS 82; G. H. IRWIN.

DIE PORMAKING AUGER BITS. No. 378,408. Patented Feb. 21, 1888 flzzomaya.

n. Pnens. mmm m. Wuhinm a. c.

UNrTnn Tarts FRANCIS THOMAS, OF CINCINNATI, AND CHARLES H. IRWIN, OFMARTINS- VILLE, OHIO; SAID THOMAS ASSIGNOR TO SAID IRWIN.

DIES FOR MAKING AUGER BITS.

SPECIFICATION forming part of Letters Patent No. 378,408, dated February21, 1888.

Application filed September 19, 1887. Serial No. 250,042.

To aZZ whom it may concern."

Be it known that we, FRANCIS THOMAS, a citizen of the United States,residing at the city of Cincinnati, in the county of Hamilton and Stateof Ohio, and CHARLES H. IRWIN, a citizen of the United States, residingat the town of Martinsville, in Clinton county and State of Ohio, haveinvented certain new and useful Improvements in Dies for MakingAugerrBits, of which the following is a specification.

Our invention relates to dies used in making that class of auger-bits inwhich the bit consists of a central spindle or stem having a [5 singleblade spirally around it, terminating at its lower end in a singlecutter, the spindle or central stern terminating in a single screw.

The main object of these dies is to properly shape the spindle and givea uniform pitch to the blade. These dies might be termed finishing orstraightening dies. The augerbit formed bythese dies is shown fullyinUnited States Letters Patent No. 306.907, dated October 21, 1884., andNo. 361,522, of April 19, 1887. y

In the accompanying drawings,forming part of this specification, Figures1 and 2 represent one set of dies, plan views.) Fig. 3 represents theauger-bit manufactured or finished by these dies. Figs. 4 and 5represent another set of dies, (2. modification.)

After the auger-bit has been properly forged under a trip-hammercontaining appropriate dies, and otherwise finished under header-dies ,5and beingin the rough, it is brought under the action of these dies.

A B represent the faces of the dies. These dies are placed in anappropriate machine, and move toward each other laterally. One half ofthe auger-bit fits in one die and the other half in the other die, sothat when brought together the dies hug every surface of the auger-bit.Across the faces of the dies is a groove, a, of a semicircular shape intransverse section. This groove is of the exact shape of the spindle band of part of the blade 61. Obliquely across the groove a are therecesses d, in which fits the spiral rib c. The

. groove a, where it approaches the inclination of the convolution ofthe blade or rib e, is of a peculiar shape-that is, of the peculiarshape of the inclination of the convolution.

The

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long groove a is to receive the shank of the auger-bit. It issemicircular in form in transverse section.

D represents a groove in which fits the cutting-point a? of theauger-bit. This point is cone-shaped, one-half of it fitting in eachdie.

In the die B there is a slight depression at Z) to receive thecutting-edge d of the auger-bit. In the present dies one half of theauger-bit is finished in one operation and the other half in anotheroperation; but we may so construct the dies that they will take in theentire length of the auger-bit in one operation. One half of theauger-bit (that is, the forging) fitting in one die, A, and the otherhalf in the other die, B, when the dies are brought to gether by anysuitable means, they entirely encompass the auger-bit and obliterateevery imperfection, bring the spindle between the convolutions and theshank in the same plane and center, make the spaces between theconvolutions equidistant, and impart a uniform pitch to the rib orblade.

In the modification, instead of having a se ries of grooves andrecesses, the groove E is provided, the entire auger-blade tilting intothis groove.

' WVhat we claim as new and of ourinvention, and desire to secure byLetters Patent of the United States, is-

In dies for finishing auger bits, the dies A B, having a series ofgrooves, as a, corresponding to and receiving one-half of the central 85spindle of the bit, and having a series of recesses, d, obliquely acrossthe grooves a, said recesses in each die corresponding in shape toone-half of one of the single convolutions of the spiral rib, thegrooves a being so shaped 0 at each end that they receive the inclinedsurfaces of the blade between the convolutions, and the recess D anddepression Z), for receiving the cutting end and point of the blade orrib, and the recess a for the shank of the bit, 5

substantially as set forth.

FRANCIS THOMAS. CHARLES H. IRWIN.

Witnesses:

J. M. Enwnnns, J osErH W. WEBER, HENRY Woonr, L. M. Porn.

